Model form is not able to save in database

I am a beginner in Django I want to save a form data in database but i am not able to save, followed some tutorials also.

form.py:

from django.forms import ModelForm

from .models import *

class listsForm(ModelForm):

    class Meta:
        model = todo
        fields = "__all__"

views.py:

from django.shortcuts import render

from .models import *

from .form import *

def index(request):

    lists = todo.objects.all()
    form = listsForm()
    context = {
        'lists':lists,
        'form':form,
    }
    if request.method == 'POST':
        form = listsForm(request.POST)
        if form.is_valid:
            form.save()

    return render(request, 'index.html', context)

models.py:

from django.db import models

class todo(models.Model):

    title = models.CharField(max_length=200)
    description = models.TextField(null=True, blank=True)
    created = models.DateField(auto_now_add=True)

    def __str__(self):
        return self.title